This invention relates generally to fasteners for articles of jewelry, and, more particularly, to a clasp for connecting the terminated ends of a jewelry chain.
The principal objective of this invention is to present the jewelry art a novel and improved means of connecting the ends of a jewelry chain which is convenient, reliable, secure and economical to produce. In pursuit of this objective, specific characteristics and qualities of jewelry fasteners have been studied resulting in the emergence of a set of design criteria that jewelry designers and manufacturers look for in a chain clasp. These criteria are: (1) ease of manipulation by the user; (2) secure and positive closure; (3) compactness of size; (4) aesthetic appearance; (5) strength and reliability; (6) simplicity of construction; (7) economy of manufacture; (8) ease of assembly to chain ends; (9) absence of sharp or snagging edges; and (10) application to a wide spectrum of utility.
In considering the present invention it will be helpful to view the current state of the art relating to jewlery fasteners. Many types of spring operated chain clasps are in use today, but the well known spring ring is by far the most widely used clasp throughout the jewelry industry.
The spring ring assembly consists of five pieces assembled in two parts. One part consists of a C-shaped tubular housing having a split jump ring attached to its outer surface for securing the device to one terminated end of a chain. A very small spring, usually of the helical type, is inserted into the tubular housing, and an arcuate post is arranged for reciprocal movement within the housing for spanning the open portion of the C-shaped housing and closing the ring. The housing is usually stacked or crimped in order to provide a backing against which the spring bears to urge the post into the closed position spanning the open portion of the housing, and a small tab is provided on the post to facilitate manual opening of the ring by retracting the post within the housing against the force of the spring. Since the post is generally too large to be secured directly to the last link at the opposite end of the chain, it is necessary to provide a relatively large jump ring on that link to which the spring ring fastener can be attached.
In addition to being comprised of a plurality of parts as described above, the conventional spring ring is also characterized by the disadvantage that the spring is formed of either a heat treated or cold drawn wire. If a jeweler were to attempt to secure the spring ring to the end link of a chain by employing conventional soldering techniques, he runs a substantial risk that the heat required to perform the soldering will deleteriously effect the spring. Therefore, either the split jump ring attached to the housing must be closed mechanically without use of heat, or the housing can be provided with a closed ring, and an additional jump ring can be used to safely attach the spring ring to the chain by soldering.
Accordingly, there has existed a need for a convenient and effective device for releasably connecting the terminated ends of a jewelry chain, which device is comprised of a relatively small number of parts and can be secured directly to the ends of the chain, and which conforms generally with the above criteria. As will become apparent from the following, the present invention satisfies that need.